Activity Description

In this activity a three students make different predictions for the following situation.

A student shines red, coherent light on a small single slit. The student will then increase the width of the opening. Three other students make a prediction about the experiment before it is conducted.

The Students's predictions are the following:

Student A: “The pattern will be unchanged.

StudentB: “The width of the pattern will increase.”

StudentC: “The width of the pattern will decrease.”

Studnts have to choose which student, if any, with which they agree.

Target Conceptual Difficulty

Inability to describe the change in a single slit pattern as the slit width and the wavelength change.

PowerPoint

Contending Students Task - Dependence of single slit pattern on slit width

Simulation

http://phet.colorado.edu/new/index.php

Click on the button marked "Play with Sims...>". On the page that appears. click in the left frame on the link "Light and Radiation" and then click on the icon or link for Wave Interference. Click on the light Tab, then click on the One Slit button. Position the barrier so that it is about in the middle of the screen. Click on the Show Screen button and then click on the Intensity Graph button to make it easier to see how the pattern changes as the spacing between the light sources change. The simulation should look about like the following.

Presentation Notes

Once the simulation is set up, explain to the students that you will change the width of the slit by dragging the slider. Once the slit width is changed, the effect is not instantaneous on the screen, you need to allow a few seconds for the diffraction pattern to catch up.

Student Results

No student results are available for this activity.

Pen and Paper Actvivities

Pen and Paper version of this activty

Follow up tipers from homework assignments, test reviews and test items